There are two clips in Hideout Helm that involve the terminals standing next to the walls.
Terminal Clip 1
With Chunky, head to the room right after the lava. Walk straight ahead to where the first terminal meets the wall, press C-left while still holding up, and then press C-up. Slightly turn left and align the middle number of the timer with the blackish spot. Setting up this angle is not very precise; if you did everything right before, you will most likely be able to clip. Exit first-person mode, don't move the control stick at all, jump, and press B in mid-air. Chunky will grab the terminal and you will be able to pull yourself through the wall by pressing up.
This trick mostly depends on the way you walk into the corner. If you mess that up, Chunky will grab the terminal and fall down immediately or pull himself up and not clip. If that happens, try changing your angle in C-up mode.
If you know you didn't get into the corner correctly, you might want to use an alternate setup. Walk into the corner, hold R and slightly move the control stick right while holding up. Chunky will be shaking due to the nature of the corner. Keep going until his movement is back to normal, then press C-up and proceed as explained above.
Terminal Clip 2
Go to the terminal to the right of the steering wheel. Face the wall and try to jump onto the left edge of it. Only use the control stick as long as you're in mid-air so you keep facing the same direction. If you land correctly, you'll be between the terminal and the ground to the left. Press up to walk straight through the wall, but don't press left at all or you will pop out of the ground.